CVE-2022-42010: Freedesktop D-Bus DoS Vulnerability

CVE-2022-42010 Overview

CVE-2022-42010 is a Denial of Service vulnerability discovered in D-Bus, a widely-used inter-process communication (IPC) mechanism for Unix-like operating systems. The vulnerability exists in versions before 1.12.24, 1.13.x and 1.14.x before 1.14.4, and 1.15.x before 1.15.2. An authenticated attacker can cause dbus-daemon and other programs that use libdbus to crash when receiving a message with certain invalid type signatures.

Critical Impact

Authenticated attackers can cause denial of service conditions by crashing the D-Bus daemon, potentially disrupting system-wide inter-process communication on affected Linux systems.

Affected Products

• Freedesktop D-Bus versions before 1.12.24
• Freedesktop D-Bus 1.13.x and 1.14.x versions before 1.14.4
• Freedesktop D-Bus 1.15.x versions before 1.15.2
• Fedora 35, 36, and 37

Discovery Timeline

• 2022-10-10 - CVE-2022-42010 published to NVD
• 2025-06-09 - Last updated in NVD database

Technical Details for CVE-2022-42010

Vulnerability Analysis

This vulnerability is classified under CWE-347, which relates to improper verification of cryptographic signatures. However, in this context, the vulnerability specifically involves improper validation of D-Bus message type signatures. When dbus-daemon or applications using libdbus receive a malformed message containing invalid type signatures, the parsing logic fails to properly handle the malformed input, resulting in a crash condition.

D-Bus is a critical component in many Linux desktop environments and system services, acting as a message bus system that allows applications to communicate with one another. The vulnerability can be exploited over a network connection, requiring low privileges and no user interaction, making it relatively accessible to authenticated attackers.

Root Cause

The root cause of this vulnerability lies in insufficient input validation within the D-Bus message signature parsing code. When processing incoming messages, the libdbus library fails to properly validate certain invalid type signature combinations before attempting to process them. This leads to unexpected program states that result in crashes when malformed signatures are encountered.

The type signature system in D-Bus uses a specific grammar to describe the types of values contained in messages. When signatures violate expected constraints but are not properly rejected during validation, the subsequent parsing operations can trigger assertion failures or memory access violations.

Attack Vector

The attack can be executed over a network connection by an authenticated user. The attacker must be able to send D-Bus messages to the target system, which typically requires local authentication or access to an exposed D-Bus socket. Once authenticated, the attacker can craft and send messages with specially constructed invalid type signatures that trigger the vulnerability.

The attack does not require any user interaction and can be executed with low complexity, making it a practical denial of service vector for authenticated users seeking to disrupt system operations.

Detection Methods for CVE-2022-42010

Indicators of Compromise

• Unexpected dbus-daemon process terminations or restarts
• Application crashes in services that depend on D-Bus for IPC
• System logs showing D-Bus assertion failures or segmentation faults
• Repeated D-Bus service restart events in systemd journal logs

Detection Strategies

• Monitor system logs for dbus-daemon crash events using log aggregation tools
• Implement process monitoring to detect abnormal dbus-daemon restarts
• Use audit logging to track D-Bus authentication events and message patterns
• Deploy endpoint detection rules for D-Bus related process crashes

Monitoring Recommendations

• Configure alerting for dbus-daemon service failures in systemd
• Monitor for repeated connection attempts from authenticated users followed by daemon crashes
• Implement baseline monitoring for D-Bus daemon stability and uptime
• Review D-Bus authentication logs for suspicious access patterns

How to Mitigate CVE-2022-42010

Immediate Actions Required

• Update D-Bus to version 1.12.24 or later for the 1.12.x branch
• Update D-Bus to version 1.14.4 or later for the 1.13.x/1.14.x branches
• Update D-Bus to version 1.15.2 or later for the 1.15.x branch
• Apply vendor-specific security patches from your Linux distribution

Patch Information

Security patches are available from Freedesktop and have been distributed through major Linux distributions. Fedora users should apply the security updates announced through the Fedora Package Announcements. Gentoo users should reference GLSA 202305-08 for patching guidance.

For detailed technical information about the vulnerability and the fix, consult the GitLab Issue #418 and the OpenWall OSS Security Discussion.

Workarounds

• Restrict D-Bus socket access to trusted users only using filesystem permissions
• Implement network segmentation to limit access to systems running vulnerable D-Bus versions
• Monitor and limit the rate of D-Bus connections from individual users
• Consider deploying application-level sandboxing for services that expose D-Bus interfaces

# Check current D-Bus version
dbus-daemon --version

# On systems using systemd, restart D-Bus after patching
sudo systemctl restart dbus

# Verify D-Bus socket permissions
ls -la /run/dbus/system_bus_socket